Ferrocene

Names

IUPAC name

ferrocene, bis(η⁵-cyclopentadienyl)iron

Other names

dicyclopentadienyl iron

Identifiers

CAS Number

102-54-5^Y

3D model (Jmol)

CHEBI:30672^N

7329^Y

U96PKG90JQ^Y

InChI=1S/2C5H5.Fe/c2*1-2-4-5-3-1;/h2*1-5H;/q2*-1;+2^Y

Key: KTWOOEGAPBSYNW-UHFFFAOYSA-N^Y
InChI=1/2C5H5.Fe/c2*1-2-4-5-3-1;/h2*1-5H;/q2*-1;+2

Key: KTWOOEGAPBSYNW-UHFFFAOYAZ

SMILES

[cH-]1cccc1.[cH-]1cccc1.[Fe+2]

Properties

Chemical formula

C₁₀H₁₀Fe

Molar mass

186.04 g/mol

Appearance

light orange powder

Odor

camphor-like

Density

1.107 g/cm³ (0 °C), 1.490 g/cm³ (20 °C)

Melting point

172.5 °C (342.5 °F; 445.6 K)

Boiling point

249 °C (480 °F; 522 K)

Solubility in water

Insoluble in water, soluble in most organic solvents

Hazards

Main hazards

Very hazardous in case of ingestion. Hazardous in case of skin contact (irritant), of eye contact (irritant), of inhalation

EU classification (DSD)

US health exposure limits (NIOSH):

PEL (Permissible)

TWA 15 mg/m³ (total) TWA 5 mg/m³ (resp)

REL (Recommended)

TWA 10 mg/m³ (total) TWA 5 mg/m³ (resp)

IDLH (Immediate danger)

N.D.

Related compounds

, nickelocene, chromocene, ruthenocene, osmocene, plumbocene

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

(what is ^YN ?)

Infobox references

Ferrocene is an organometallic compound with the formula Fe(C₅H₅)₂. It is the prototypical metallocene, a type of organometallic chemical compound consisting of two cyclopentadienyl rings bound on opposite sides of a central metal atom. Such organometallic compounds are also known as sandwich compounds. The rapid growth of organometallic chemistry is often attributed to the excitement arising from the discovery of ferrocene and its many analogues.

Ferrocene was first prepared unintentionally. In 1951, Pauson and Kealy at Duquesne University reported the reaction of cyclopentadienyl magnesium bromide and ferric chloride with the goal of oxidatively coupling the diene to prepare fulvalene. Instead, they obtained a light orange powder of "remarkable stability". A second group at British Oxygen also unknowingly discovered ferrocene. Miller, Tebboth and Tremaine were trying to synthesise amines from hydrocarbons such as cyclopentadiene and ammonia in a modification of the Haber process. They published this result in 1952 although the actual work was done three years earlier. The stability of the new organoiron compound was accorded to the aromatic character of the negatively charged cyclopentadienyls, but they were not the ones to recognize the η⁵ (pentahapto) sandwich structure.

Robert Burns Woodward and Geoffrey Wilkinson deduced the structure based on its reactivity. Independently Ernst Otto Fischer also came to the conclusion of the sandwich structure and started to synthesize other metallocenes such as nickelocene and .

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